Denying the opposition's claim to victory over Yugoslav President Slobodan Milosevic, the state-controlled Federal Electoral Commission on Tuesday said a runoff election must be held because no presidential candidate won an outright majority.

Opposition members were expelled early Monday from the federal commission certifying the results of Yugoslavia's weekend elections, adding to widespread suspicion that President Slobodan Milosevic is trying to fake a victory. But Vojislav Kostunica, the opposition candidate backed by a coalition of 18 parties, told reporters that he considered himself president-elect, based on unofficial results showing him with 55.3% of the vote to Milosevic's 34.3%.

As unofficial results from national elections trickled in through the night, supporters of Yugoslav President Slobodan Milosevic and his chief rival, Vojislav Kostunica, both claimed victory in the early hours today. But after a day of voting that the opposition said was rife with tampering and intimidation, many here were still doubting that Milosevic would accept the results if he lost.

Faced with the strongest challenge in his 13 years of rule, Yugoslav President Slobodan Milosevic is fighting for reelection Sunday amid Western and opposition fears that he will win the only way the polls say he can: through massive vote fraud. Milosevic is losing his almost hypnotic hold over most Serbs, who once revered him as a national hero. If he steals the election Sunday, or in a second round, Milosevic will have sacrificed his last vestige of legitimacy.